A patient genetically diagnosed with X-linked agammaglobulinemia repeatedly developed bacteremia due to Campylobacter coli (C. coli) for one year and seven months in spite of immunoglobulin replacement therapy. Throughout the clinical course, C. coli with identical genetic patterns was repeatedly isolated from both blood and stool cultures, thus indicating that the patient had latent intestinal infection. The bacteremia was always accompanied by reactive arthritis. Since the immunoglobulin level was extremely low with severe B cell deficiency, the reactive arthritis must have been induced in a humoral immunity-independent manner. Adding oral minocycline following intravenous meropenem was very effective; the stool cultures became negative and the patient has been well for more than one year without relapse of bacteremia.